1. Field of the Invention
The present invention relates to a multiple freedom manipulator preferable to forceps for use in low invasion operation or the like.
2. Description of the Related Art
Low invasion operations attract many attentions in the field of medical operation and have been introduced into the same in recent years. Although in conventional operations a body of a patient is largely cut as in abdominal surgery the low invasion operation is an operation which is realized only by cutting a body as possible as slightly and in which an operator treats a diseased part by inserting an elongated rod-shaped forceps and a surgical knife while observing the diseased part mainly with the aid of an endoscope.
The low invasion operation cures diseases by inserting an elongated rod-shaped forceps and a surgical knife from a small hole while watching a diseased part using an endoscope as described above, so that any damage of a normal portion can be reduced to make a contribution to patients, but, on the one hand, there are problems to make difficult the operation of a treatment tool because the tool is restricted by the hole. To solve the problem a forceps capable of moving the tip end of the forceps are now in studies and developments.
As treatment tools having flexibility at the tip end of a forceps there have been hitherto proposed a forceps disclosed in reference 1 having one-degree-of-freedom of rotation without actuator and a master/slave forceps disclosed in reference 2 having two-degree-of-freedom and gripping.
However, in order to take an arbitrary attitude the tip end of the forceps requires two or more-degree-of-freedom so that the forceps disclosed in reference 1 does not provide enough operationability.
Further, the forceps disclosed in reference 2 suffers from a difficulty that introduction and operation thereof are difficult in view of the magnitude and costs thereof and a difficulty that satisfactory force feedback cannot be obtained. For this, the forceps is unlikely to be adopted because a space in an operating room is insufficient as well as excessive force might be applied to the forceps because no enough force is transmitted thereupon.
There are known an integrated master/slave forceps disclosed in reference 3 and a forceps disclosed in reference 4 as those having two-degree-of-freedom and being smaller than that disclosed in reference 2.
Although it is intended the integrated master/slave forceps disclosed in reference 3 is miniaturized by driving only two-degree-of-freedom of rotation and the gripping of the tip end of the forceps, it requires external devises such as a power supply and a support mechanism and it has no feedback of force with respect to the freedom driven by a DC motor.
Further, the forceps disclosed in reference 4 suffers from a difficulty where rotary axes of the two-degree-of-freedom of rotation of the tip end of the forceps do not intersect to lower operationability, and has the possibility that a link swells out at the time of bending in view of the structure thereof to wind organs etc. outside a view of an endoscope. Moreover, when notice is taken of only a mechanism of adding two-degree-of-freedom on the tip end of the forceps, although there are known those disclosed in reference 5 other than those disclosed above and those disclosed in reference 6, they employ a wire to cause a severe influence of static friction and also have low rigidity of a member for transmitting power.
Reference 1: U.S. Pat. No. 5,702,408 Specification
Reference 2: International Publication WO97/43943 Pamphlet
Reference 3: Japanese Unexamined Patent Publication No.2004-105451
Reference 4: Japanese Unexamined Patent Publication No. 2004-89482
Reference 5: Japanese Unexamined Patent Publication No. 2004-187798
Reference 6: U.S. Pat. application No. 2004/0162547
Although various forceps have been proposed heretofore as described above, the forceps disclosed in reference 1 can not offer satisfactory operationability, and the one disclosed in reference 2 is difficult in its introduction and operation from the viewpoint of the size and cost, and does not present satisfactory force feedback.
Further, the forceps disclosed in reference 3 requires external apparatuses such as a power supply and a support mechanism with no force feedback, and the forceps disclosed in reference 4 has lower operation property and allows a link to be swelled outside upon its bending.
In contrast, those disclosed in references 5, 6 suffer from a severe influence of static friction and has lower rigidity of a member for transmitting power.
Since the low invasion operations require a high technique of operators, a forceps having higher operationability is desired, and a forceps having two-degree-of-freedom rotation and gripping freedom at the tip end of the forceps and being excellent in operationability and simple in maintenance and operation is strongly desired. There are however not proposed hitherto ones satisfying such requirements.